A broad range of applications require high-voltage, high-power, variable-voltage sources with pulse-switching capabilities. Such applications include radar transmitters, X-ray machines, and semiconductor wafer manufacturing equipment. These machines and equipment employ such high-power amplifiers as cross-field amplifiers, traveling-wave tubes, magnetrons, and klystron amplifiers (collectively referred to as vacuum-electron devices). A number of high-power modulators are adapted to deliver pulsed power to these types of high-power amplifiers.
Conventional high-power modulators can be implemented using high-power vacuum tubes, but the technology is moving toward solid-state high-power switches, which are generally smaller and more robust. Insulated-gate bipolar transistors (IGBTs) are a common solid-state switch used in high-voltage applications. For a more detailed discussion of one type of conventional high-power modulator that employs IGBTs, see U.S. Pat. Nos. 5,444,610 and 5,646,833, both to Gaudreau et al., issued Aug. 22, 1995, and Jul. 8, 1997, respectively. Both of these documents are incorporated herein by reference.
IGBT-based high-power modulators provide excellent high-power, high-speed switching performance. There is always room for improvement, however, as competitive technology markets are ever watchful for cost-competitive systems that offer improved efficiency, reliability, speed performance, or a combination of these.